An ab initio study of mutual neutralization in Na++H- collisions

First principles calculations of mutual neutralization in Na+ + H- collisio ns have been performed for collision energies between 0.01 and 100 eV. A te n-state molecular expansion has been employed with a quantal description of the relative motion and a diabatic nb initio calculation for the two activ e electrons. While results for the total neutralization cross section are g enerally within 15% of those obtained by Janev and Radulovic (1978), cross sections into the less populated final states differ much more, by in exces s of an order of magnitude for the 3p level. At 100 eV satisfactory agreeme nt is obtained with the results of Olson and Kimura (1985). The low-tempera ture rate coefficient for mutual neutralization is calculated to be 3.0 x 1 0(-7) (T/300 K)(-1/2) cm(3) s(-1). Cross sections for ion-pair production i n Na(3l) + H collisions have also been determined, showing substantial diff erences from the results of Janev and Radulovic (1978), particularly for pr oduction from 3s at low energy. Differences of 5% and 35% from the calculat ions of Olson and Kimura (1985) for 3s and 3p, respectively, at 100 eV are obtained.